1. Field of the Invention
The present invention relates to a signaling system for simultaneously autonomously setting a spare path when setting a working path passing through rings by signaling in a network including a plurality of rings connected to each other at a plurality of nodes.
2. Description of the Related Art
In a SONET/SDH network, as technology for setting paths by signaling, for example, there is the RSVP-TE expansion of the GMPLS (RFC3473). As technology for further expanding the RSVP-TE and simultaneously and autonomously setting the spare paths of the rings as well, there are the following:
(a) “Labeling system” (Japanese Patent Application No. 2005-102092 filed on Mar. 31, 2005)
(b) “Dynamic control system of segment recovery” (draft-ietf-ccamp-gmpls-segment-recovery-01.txt)
The system of (a) is a system having pair information of nodes connecting rings among the nodes present in each ring and setting spare paths by the drop-and-continue system. The system of (b) is a system calculating the route of a spare path and starting the signaling of the spare path when judging that the home node is a branch.
This related art is for example disclosed in Japanese Patent Publication (A) No. 2003-23436, Japanese Patent Publication (A) No. 2003-101558, and Japanese Patent Publication (A) No. 2000-236347.
The labeling system of the system of (a) of the related art cannot be used to handle the dual transmit system. It can only be used to handle the drop-and-continue system. Therefore, even when the dual transmit system is better in efficiency of utilization of the spare path network resources depending on the network configuration or route of the working path, the spare path has to be set by the drop-and-continue system. There was therefore the disadvantage of an extremely poor efficiency of utilization of the spare path network resources. Note that the dual transmit system is the system where the working path is branched into a working path and spare path at the first node (ADD node) which it enters, while the drop-and-continue system is the system where the working path is branched into a working path and spare path at the node dropping from one ring to an adjoining ring.
In the segment recovery dynamic control system of the system of (b) of the related art, basically a mesh network is covered and a ring is not considered, so at which node the rings are connected is not clear. There was therefore the disadvantage that a spare route for correct operation could not be set.